Paper - A quantitative study of the hypophysis of the human anencephalic fetus: Difference between revisions

From Embryology
mNo edit summary
Line 22: Line 22:
From the Department of Anatomy, University of M innesota, M innoapolis, Minn.
From the Department of Anatomy, University of M innesota, M innoapolis, Minn.


INTRODUCTION
==Introduction==


The question of the presence or the absence of the hypophysis in
The question of the presence or the absence of the hypophysis in the anencephalic fetus has been of special significance in connection with the subject of the function and interrelationship of the ductless glands. Some have even attributed this abnormality to a disturbance of the endocrine system. Previous to 1921 the general belief was that an hypophysis was frequently absent in anencephalics and when present was usually described as being diflerent from the normal gland. No quantitative methods have been applied, consequently the literature is based on qualitative observations only.
the anencephalic fetus has been of special significance in connection
with the subject of the function and interrelationship of the ductless
glands. Some have even attributed this abnormality to a disturbance of the endocrine system. Previous to 1921 the general belief
was that an hypophysis was frequently absent in anencephalics and
when present was usually described as being diflerent from the normal gland. No quantitative methods have been applied, consequently the literature is based on qualitative observations only.


It is the purpose of this investigation to apply quantitative
It is the purpose of this investigation to apply quantitative methods to these abnormal specimens and when the organ is present to compare it with that of the normal. In order to bring the subject to its present status the principal contributions are summarized below.
methods to these abnormal specimens and when the organ is present
to compare it with that of the normal. In order to bring the subject
to its present status the principal contributions are summarized below.


REVIEW OF THE LITERATURE
==Review of the Literature==


Ballantyne 1 has described forty-five anencephalic fetuses and
Ballantyne 1 has described forty-five anencephalic fetuses and states that “ the hypophysis rarely occurs.” Schwalbe 2 says the hypophysis is sometimes present and in a large number of cases there is accessory hypophyseal tissue. Haberfeld 3 examined three cases of anencephaly and reported an hypophysis as present in each. In one instance a pars nervosa was found in the upper part of the cralnio-.
states that “ the hypophysis rarely occurs.” Schwalbe 2 says the
hypophysis is sometimes present and in a large number of cases there
is accessory hypophyseal tissue. Haberfeld 3 examined three cases of
anencephaly and reported an hypophysis as present in each. In one


instance a pars nervosa was found in the upper part of the cralnio-.
pharyngeal canal. The glandular portions, in this instance,‘ extended through the canal and only a small polyp was present at either end. Brown 4 examined five specimens of anencephalic fetuses and failed to find the hypophysis. He concluded, therefore, that the condition


pharyngeal canal. The glandular portions, in this instance,‘ extended
of apituitarism was normal for anencephaly. Mauksch 5 found an hypophysis in nine cases of this monstrosity. In five of these, he described a pharyngeal hypophysis with a par ‘ Received for publication September 28, 1926.
through the canal and only a small polyp was present at either end.
Brown 4 examined five specimens of anencephalic fetuses and failed
to find the hypophysis. He concluded, therefore, that the condition


of apituitarism was normal for anencephaly.
tially or totally patent craniopharyngeal canal which contained blood vessels and hypophyseal tissue. All three lobes were present in only two of the nine glands. When there was no posterior lobe (pars nervosa), he did not observe a pars intermedia and thus considered the hypophysis in such cases to consist of pars anterior only. In one instance he found the upper surface of the connective tissue capsule to contain a small neuroglial structure which was in contact neither with the brain tissue nor with the hypophysis. There was no intermediate glandular portion discernible. In two of the specimens the pars nervosa was found to be a small basophilic structure of neuroglial elements located on a concavity of the glandular part. He noticed a pars intermedia in contact with the latter but thought it appeared abnormal and incomplete. He found the pars anterior to be very vascular and the parenchyma in the form of cords surrounded by sinuses filled with blood.
Mauksch 5 found an hypophysis in nine cases of this monstrosity.
In five of these, he described a pharyngeal hypophysis with a par
‘ Received for publication September 28, 1926.


tially or totally patent craniopharyngeal canal which contained
Kohn 5 verified the report of Mauksch 5 as to the occurrence of the hypophysis. He investigated eleven cases of anencephaly and found an hypophysis in each. He likewise found the gland to be abnormal in structure. In only three of the specimens did he find a pars nervosa. He concluded that the pars intermedia and pars nervosa as well as the pars tuberalis are usually lacking. If the pars nervosa was not present, he thought the intermediate lobe was also absent. He reported that the cells of the pars anterior were normally differentiated. In addition he described a cell which he thought occurred but seldom in the normal fetal hypophysis. According to him, this latter mentioned type was present in large numbers in the anencephalic hypophysis. Such a cell type appeared to be larger than the chromophile cells and stained slightly basophilic or neutrophilic with Mallory’s triple connective tissue stain.
blood vessels and hypophyseal tissue. All three lobes were present
in only two of the nine glands. When there was no posterior lobe
(pars nervosa), he did not observe a pars intermedia and thus considered the hypophysis in such cases to consist of pars anterior only.
In one instance he found the upper surface of the connective tissue
capsule to contain a small neuroglial structure which was in contact
neither with the brain tissue nor with the hypophysis. There was no
intermediate glandular portion discernible. In two of the specimens
the pars nervosa was found to be a small basophilic structure of
neuroglial elements located on a concavity of the glandular part. He
noticed a pars intermedia in contact with the latter but thought it
appeared abnormal and incomplete. He found the pars anterior to
be very vascular and the parenchyma in the form of cords surrounded by sinuses filled with blood.
 
Kohn 5 verified the report of Mauksch 5 as to the occurrence of
the hypophysis. He investigated eleven cases of anencephaly and
found an hypophysis in each. He likewise found the gland to be
abnormal in structure. In only three of the specimens did he find
a pars nervosa. He concluded that the pars intermedia and pars
nervosa as well as the pars tuberalis are usually lacking. If the pars
nervosa was not present, he thought the intermediate lobe was also
absent. He reported that the cells of the pars anterior were normally
differentiated. In addition he described a cell which he thought
occurred but seldom in the normal fetal hypophysis. According to
him, this latter mentioned type was present in large numbers in the
anencephalic hypophysis. Such a cell type appeared to be larger
than the chromophile cells and stained slightly basophilic or neutrophilic with Mallory’s triple connective tissue stain.


Wrete 7 found a hypophysis to be present in a case of encephalomyeloschisis totalis of an embryo of the seventh week. ‘
Wrete 7 found a hypophysis to be present in a case of encephalomyeloschisis totalis of an embryo of the seventh week. ‘


MATERIAL AND METHODS
==Material and Methods==


The material used in this study consisted of thirty-two anencephalic fetuses which were obtained from the Department of Pathology, University of Minnesota. Most of the material had been
The material used in this study consisted of thirty-two anencephalic fetuses which were obtained from the Department of Pathology, University of Minnesota. Most of the material had been previously preserved in IO per cent formalin in which it had remained for a year or more in some instances.
previously preserved in IO per cent formalin in which it had remained for a year or more in some instances.


Twenty-seven of the thirty-two fetuses were females, the remaining five being males. They ranged in age from about the fifth fetal
Twenty-seven of the thirty-two fetuses were females, the remaining five being males. They ranged in age from about the fifth fetal month to full term. The ages of the fetuses were determined by means of a formula used by Nafiagas 3 for conversion of the leg length (distance from the greater trochanter to the base of the heel) of the anencephalic fetus into total body length of a normal fetus. Then by applying to the result the formula of Scammon and Calkins 9 for converting the crown-heel measurement into terms of age in fetal months, the latter was determined. The formula given
month to full term. The ages of the fetuses were determined by
means of a formula used by Nafiagas 3 for conversion of the leg
length (distance from the greater trochanter to the base of the
heel) of the anencephalic fetus into total body length of a normal
fetus. Then by applying to the result the formula of Scammon and
Calkins 9 for converting the crown-heel measurement into terms of
age in fetal months, the latter was determined. The formula given


by Nafiagas is as follows:
by Nafiagas is as follows:
Line 104: Line 52:
Crown-heel (cm.) = 3%: leg length (cm.) + 0.7
Crown-heel (cm.) = 3%: leg length (cm.) + 0.7


The formula developed by Scammon and Calkins gives the age in
The formula developed by Scammon and Calkins gives the age in fetal months or “T” when “L” is the crown-heel measurement in centimeters.
fetal months or “T” when “L” is the crown-heel measurement in
 
centimeters.




The relative and absolute volumes of the parts of the gland were
The relative and absolute volumes of the parts of the gland were determined by the paper-weight method as described by Rasmussen and Herrick.” For a comparison of the abnormal with the normal gland, data available (Covell 11) on the hypophyses of sixty-two normal fetuses were used.
determined by the paper-weight method as described by Rasmussen
and Herrick.” For a comparison of the abnormal with the normal
gland, data available (Covell 11) on the hypophyses of sixty-two
normal fetuses were used.


The relative amount of blood in the pars anterior of the hypophysis was approximated by projecting areas of sections 10 microns
The relative amount of blood in the pars anterior of the hypophysis was approximated by projecting areas of sections 10 microns thick of this portion of the gland at a magnification of about 7 50 times. five fields were chosen on each of three different levels, two of the fields being near the periphery of the gland, one centrally located and the remaining two intermediate between the periphery and central parts. The vascular areas in each of the fields were outlined with a hard lead pencil. The relative amount of blood in the pars anterior was then ascertained by weighing the paper areas representing the blood and those representing the fibrous and glandular tissue, and dividing the weight of the vascular areas in paper by the total paper—weight.
thick of this portion of the gland at a magnification of about 7 50
times. five fields were chosen on each of three different levels, two
of the fields being near the periphery of the gland, one centrally
located and the remaining two intermediate between the periphery
and central parts. The vascular areas in each of the fields were outlined with a hard lead pencil. The relative amount of blood in the
pars anterior was then ascertained by weighing the paper areas representing the blood and those representing the fibrous and glandular tissue, and dividing the weight of the vascular areas in paper by
the total paper—weight.


For the normal gland, a section approximately one-half of the
For the normal gland, a section approximately one-half of the way through the gland was used and five fields were outlined on it. The relative volume of the blood was found to be very nearly identical withfthat determined by the use of the three levels and the fifteen fields.
way through the gland was used and five fields were outlined on it.
The relative volume of the blood was found to be very nearly identical withfthat determined by the use of the three levels and the
fifteen fields.


GENERAL DESCRIPTION OF THE HYPOPHYSIS
==General Description of the Hypophysis==


Of the thirty-two specimens of the anencephalic fetus examined,
Of the thirty-two specimens of the anencephalic fetus examined, an hypophysis was present in each instance. Such findings are in accordance with the more recent investigations on this monstrosity but in contradiction to the earlier work. It would appear that the earlier work was of a gross nature so that the small amount of hypophyseal tissue which lies on the malformed basis cranii may have been overlooked.
an hypophysis was present in each instance. Such findings are in
accordance with the more recent investigations on this monstrosity
but in contradiction to the earlier work. It would appear that the
earlier work was of a gross nature so that the small amount of hypophyseal tissue which lies on the malformed basis cranii may have
been overlooked.


The hypophyseal fossa is usually lacking or at the most only
The hypophyseal fossa is usually lacking or at the most only feebly developed. No trace of the clinoid processes or dorsum sella is evident. Occasionally the anterior clinoid processes are slightly developed and so form a narrow fossa for the most anterior portion of the gland. A diaphragma sella is lacking, probably because of the absence of the clinoid processes.
feebly developed. No trace of the clinoid processes or dorsum sella
is evident. Occasionally the anterior clinoid processes are slightly
developed and so form a narrow fossa for the most anterior portion
of the gland. A diaphragma sella is lacking, probably because of the
absence of the clinoid processes.


The hypophysis may then be said, to lie on a flattened sella turcica
The hypophysis may then be said, to lie on a flattened sella turcica covered over by membranes, vascular tissue and in some instances a small amount of brain tissue. Macroscopically it presents a flat triangular shape with the apex directed dorsally. The base of this mass is formed by two lateral spreading portions and the apex of one central mass. Such a shape no doubt is of embryologic significance because it is known that the glandular portion (pars anterior) grows in early fetal life by means of two lateral and one central buds from the ventral side of Rathke’s pouch. This form subsequently changes in the course of normal development because the gland soon approximates the shape of the fossa in which it is situated. Macroscopically, the neural elements (pars nervosa) of the gland, when present, appear as an irregularly shaped opaque mass on the dorso— posterior surface of the larger glandular portion. An infundibular stalk is lacking and only a thin cord of membrane remains to attach the gland to the overlying tissues. Microscopically, the hypophysis of the anencephalic fetus presents several striking differences when compared with the gland from the normal fetus. In the first place, the three lobes may not all be present. In only six of the seventeen specimens studied did the hypophysis consist of three lobes. In eleven instances there was no pars nervosa evident. In four of the latter a pars intermedia could be distinguished, whfle in the remaining seven the pars anterior appeared to comprise the total gland volume.
covered over by membranes, vascular tissue and in some instances a
small amount of brain tissue. Macroscopically it presents a flat
triangular shape with the apex directed dorsally. The base of this
mass is formed by two lateral spreading portions and the apex of one
central mass. Such a shape no doubt is of embryologic significance
because it is known that the glandular portion (pars anterior) grows
in early fetal life by means of two lateral and one central buds from
the ventral side of Rathke’s pouch. This form subsequently changes
in the course of normal development because the gland soon approximates the shape of the fossa in which it is situated. Macroscopically, the neural elements (pars nervosa) of the gland, when
present, appear as an irregularly shaped opaque mass on the dorso—
posterior surface of the larger glandular portion. An infundibular
stalk is lacking and only a thin cord of membrane remains to attach
the gland to the overlying tissues. Microscopically, the hypophysis
of the anencephalic fetus presents several striking differences when
compared with the gland from the normal fetus. In the first place,
the three lobes may not all be present. In only six of the seventeen
specimens studied did the hypophysis consist of three lobes. In
eleven instances there was no pars nervosa evident. In four of the
latter a pars intermedia could be distinguished, whfle in the remaining seven the pars anterior appeared to comprise the total gland
volume.


The extreme vascularity of the gland, particularly of the pars
The extreme vascularity of the gland, particularly of the pars anterior, presents a marked difierence from that of the normal. Especially about the periphery of the anterior lobe the sinuses are dilated to such an extent that the parenchyma is reduced to narrow epithelial cords which appear to be surrounded by blood spaces. Toward the center of the pars anterior, the sinuses are usually less dilated with blood.
anterior, presents a marked difierence from that of the normal.
Especially about the periphery of the anterior lobe the sinuses are
dilated to such an extent that the parenchyma is reduced to narrow
epithelial cords which appear to be surrounded by blood spaces.
Toward the center of the pars anterior, the sinuses are usually less
dilated with blood.


Trabeculae radiate through the pars anterior and contain numerous blood vessels. Occasionally there is a band of fibrous tissue separating the main bulk of the anterior lobe from the thin epithelial
Trabeculae radiate through the pars anterior and contain numerous blood vessels. Occasionally there is a band of fibrous tissue separating the main bulk of the anterior lobe from the thin epithelial strip which borders the hypophyseal cavity. Likewise the pars intermedia may be separated from the pars nervosa by a thin band of fibrous tissue. The capsule of connective tissue about the gland is well developed and appears to be more extensive than in the normal hypophysis.
strip which borders the hypophyseal cavity. Likewise the pars intermedia may be separated from the pars nervosa by a thin band of
fibrous tissue. The capsule of connective tissue about the gland is
well developed and appears to be more extensive than in the normal
hypophysis.


RELATIVE AND ABSOLUTE VOLUMES on THE GLAND
==Relative and Absolute Volumes of the Gland and its Parts==
AND ITS PARTS e


A. Weight of the total gland. In Table I are given the absolute
A. Weight of the total gland. In Table I are given the absolute volumes of seventeen hypophyses and their lobes. It is evident that there is considerable individual variation in the total weight of the gland for fetuses of about the same age. The six observations for fetuses of the fifth to the sixth fetal months have a range of 29. 3 to 69.6 mg. and an average of 42. 3 mg. The range as observed from six specimens of the sixth to the seventh fetal months is 29.2 to 85.6 mg. with an average of 58.5 mg. Four hypophyses from fetuses of the seventh to the eighth fetal months show a range of 3 5.0 to 7 3.8 mg. and an average of 5 5.1 mg. The intervals from the eighth fetal month to birth are represented by only one observation. The age of the latter was calculated as 10.16 fetal months and the hypophysis weight was found to be 113.2 mg.
volumes of seventeen hypophyses and their lobes. It is evident that
there is considerable individual variation in the total weight of the
gland for fetuses of about the same age. The six observations for
fetuses of the fifth to the sixth fetal months have a range of 29. 3 to
69.6 mg. and an average of 42. 3 mg. The range as observed from six
specimens of the sixth to the seventh fetal months is 29.2 to 85.6 mg.
with an average of 58.5 mg. Four hypophyses from fetuses of the
seventh to the eighth fetal months show a range of 3 5.0 to 7 3.8 mg.
and an average of 5 5.1 mg. The intervals from the eighth fetal
month to birth are represented by only one observation. The age of
the latter was calculated as 10.16 fetal months and the hypophysis
weight was found to be 113.2 mg.


B. Weight of the pars anterior. Considerable variation is likewise
B. Weight of the pars anterior. Considerable variation is likewise evident in the weights of the pars anterior. For the fifth to the sixth months, the range is 29.3 to 65.4 mg. and the average is 40.9 mg. The weights of this lobe in specimens of the sixth to the seventh fetal months show a range of 28.9 to 85.6 mg. with an average of 57.8 mg. From the seventh to the eighth fetal months, the range is 34.6 to
evident in the weights of the pars anterior. For the fifth to the sixth
months, the range is 29.3 to 65.4 mg. and the average is 40.9 mg.
The weights of this lobe in specimens of the sixth to the seventh fetal
months show a range of 28.9 to 85.6 mg. with an average of 57.8 mg.
From the seventh to the eighth fetal months, the range is 34.6 to


TABLE 1
TABLE 1
Line 211: Line 83:
Absolute Volume of the Gland and its Parts in Seventeen Specimens of Anencephaly
Absolute Volume of the Gland and its Parts in Seventeen Specimens of Anencephaly


;
Leg r£‘(’)‘tl:’l Age in Hygggh- a.I:1l:::l§0l' ncfrgssa Case number Sex length length fetal weight weight weight weight on computed months mg. mg. mg. mg. cm. c9 . . . . . . . . . . . . . . F 10.2 | 25.34 5.38 38.0 36.6 0.9 0.5
 
Leg r£‘(’)‘tl:’l Age in Hygggh- a.I:1l:::l§0l' ncfrgssa
Case number Sex length length fetal weight weight weight weight
on computed months mg. mg. mg. mg.
cm.
c9 . . . . . . . . . . . . . . F 10.2 | 25.34 5.38 38.0 36.6 0.9 0.5


c2 . . . . . . . . . . . . . . M 10.7 26.51 5.56 41.6 40.8 0.8
c2 . . . . . . . . . . . . . . M 10.7 26.51 5.56 41.6 40.8 0.8
Line 249: Line 115:
CI4 . . . . . . . . . . . . . F 16.6 40.23 7.95 73.8 71.4 2.0 0.4
CI4 . . . . . . . . . . . . . F 16.6 40.23 7.95 73.8 71.4 2.0 0.4


c4—18 . . . . . . . . . . . F 21.2 50.93 10.16 113.2 106. 1.6 5.3
c4—18 . . . . . . . . . . . F 21.2 50.93 10.16 113.2 106. 1.6 5.3 TABLE 2
TABLE 2


Relative Volumes of the Lobes of the Anencephalic Hypophysis
Relative Volumes of the Lobes of the Anencephalic Hypophysis




Case number I 3 in Pars anterior Pars inter-media Pars nervosa
Case number I 3 in Pars anterior Pars inter-media Pars nervosa etal months per cent per cent per cent c9 . . . . . . . . . . . . . . . . . . . . . . . 5 38 96.33 2 36 1 31
etal months
per cent per cent per cent
c9 . . . . . . . . . . . . . . . . . . . . . . . 5 38 96.33 2 36 1 31


c2 . . . . . . . . . . . . . . . . . . . . . . . 5 56 98.08 1 92
c2 . . . . . . . . . . . . . . . . . . . . . . . 5 56 98.08 1 92
Line 276: Line 138:
c5 . . . . . . . . . . . . . . . . . . . . . . . 7.47 96.50 3 50 . .
c5 . . . . . . . . . . . . . . . . . . . . . . . 7.47 96.50 3 50 . .


c14 . . . . . . . . . . . . . . . . . . . . . . 7.95 96.75 2 71 0.54
c14 . . . . . . . . . . . . . . . . . . . . . . 7.95 96.75 2 71 0.54  
HYPOPHYSIS OF THE ANENCEPHALIC FETUS 2 3


71.4 mg. and the average is 54.1 mg. In the one gland of a fetus of
10.16 fetal months the weight of the pars anterior is 106.3 mg.


C. Weights of the partes intermedia and nervosa. The absolute
volumes of the partes intermedia and nervosa are of very little significance because of the extreme variations. They are, however, of importance for a comparison with the normal Weights.


D. Relative volumes of the parts (lobes). The relative volumes of
71.4 mg. and the average is 54.1 mg. In the one gland of a fetus of 10.16 fetal months the weight of the pars anterior is 106.3 mg.
the various lobes of the hypophysis are given in Table 2. Because
of the limited number of cases and the apparent irregularities in the
partes intermedia and nervosa, the relative volumes will be con
3 sidered without respect to fetal age. The anterior lobe comprises


about 93.9 to 1oo per cent of the total gland volume. In the eleven
C. Weights of the partes intermedia and nervosa. The absolute volumes of the partes intermedia and nervosa are of very little significance because of the extreme variations. They are, however, of importance for a comparison with the normal Weights.
instances in which a pars intermedia was present, it is seen to comprise 1.14 to 3.59 per cent of the total gland Weight. The pars
nervosa which occurs in only six of the seventeen cases varies in relative volume from 0.54 to 4.69 per cent. From the above percentage
values it is evident that most of the hypophysis is pars anterior and
only a small part is intermediate and posterior lobes. In only one
instance does the pars nervosa exceed the pars intermedia in relative
as well as absolute volume.


VOLUMEIRIC ANALYSIS on THE PARS ANTERIOR
D. Relative volumes of the parts (lobes). The relative volumes of the various lobes of the hypophysis are given in Table 2. Because of the limited number of cases and the apparent irregularities in the partes intermedia and nervosa, the relative volumes will be con 3 sidered without respect to fetal age. The anterior lobe comprises about 93.9 to 1oo per cent of the total gland volume. In the eleven instances in which a pars intermedia was present, it is seen to comprise 1.14 to 3.59 per cent of the total gland Weight. The pars nervosa which occurs in only six of the seventeen cases varies in relative volume from 0.54 to 4.69 per cent. From the above percentage values it is evident that most of the hypophysis is pars anterior and only a small part is intermediate and posterior lobes. In only one instance does the pars nervosa exceed the pars intermedia in relative as well as absolute volume.


A. Relative volume of the blood. Because of the engorged sinuses of
==Volumetric Analysis of the Pars Anterior==
the pars anterior and the prominent trabeculae, it was found necessary to determine the relative amounts of each. This was accomplished by means of the paper-weight method as already described.
The results are tabulated in Table 3. The figures for the relative
vascularity appear to vary from about 2 5 to 50 per cent for individual estimations. The average for the fifteen determinations is 38.98
per cent.


B. Relative volume of the trabeculae. The relative amounts of
A. Relative volume of the blood. Because of the engorged sinuses of the pars anterior and the prominent trabeculae, it was found necessary to determine the relative amounts of each. This was accomplished by means of the paper-weight method as already described. The results are tabulated in Table 3. The figures for the relative vascularity appear to vary from about 2 5 to 50 per cent for individual estimations. The average for the fifteen determinations is 38.98 per cent.
trabeculae present in the gland range from about o. 5 per cent to
nearly 4 per cent. The average for the series is 1. 58 per cent. This
figure represents only the larger masses of fibrous tissue in the pars
anterior. The finer connective tissue framework is included with the
percentage figure for the parenchyma, the average for which is
59.44 per cent of the volume of the pars anterior. The range is
approximately 45 to 77 per cent.




It is thus obvious that considerable of the absolute volume of the
B. Relative volume of the trabeculae. The relative amounts of trabeculae present in the gland range from about o. 5 per cent to nearly 4 per cent. The average for the series is 1. 58 per cent. This figure represents only the larger masses of fibrous tissue in the pars anterior. The finer connective tissue framework is included with the percentage figure for the parenchyma, the average for which is 59.44 per cent of the volume of the pars anterior. The range is approximately 45 to 77 per cent.
anterior lobe is due to the presence of blood in the sinuses. From the
 
 
It is thus obvious that considerable of the absolute volume of the anterior lobe is due to the presence of blood in the sinuses. From the relative averages cited above, it may be said that approximately two-fifths of this part of the gland is composed of vascular and fibrous stroma. The remaining three-fifths is comprised of parenchyma and finer fibrous stroma. Such an analysis is of value in determining the actual amount of glandular tissue which is present. The large amounts of blood apparently influence the volume of the anencephalic hypophysis to a marked degree.
 


relative averages cited above, it may be said that approximately
two-fifths of this part of the gland is composed of vascular and


TABLE 3
TABLE 3
Line 327: Line 164:
Volumetric Analysis of the Components of the Pars Anterior
Volumetric Analysis of the Components of the Pars Anterior


 


Case number U Blood Trabeculae filll) (1_"g1b°:)Yu:“;;'§ga
Case number U Blood Trabeculae filll) (1_"g1b°:)Yu:“;;'§ga I fier cent per cent per cent c9 . . . . . . . . . . . . . . . . . .8 . . . . . . . . . . . . 38.18 3.98 57.84
I fier cent per cent per cent
c9 . . . . . . . . . . . . . . . . . .8 . . . . . . . . . . . . 38.18 3.98 57.84


c2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' 40.37 V 0.49 59.14
c2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' 40.37 V 0.49 59.14
Line 364: Line 198:




fibrous stroma. The remaining three-fifths is comprised of parenchyma and finer fibrous stroma. Such an analysis is of value in
determining the actual amount of glandular tissue which is present.
The large amounts of blood apparently influence the volume of the
anencephalic hypophysis to a marked degree.


DISCUSSION
==Discussion==
 
The shape of the anencephalic hypophysis is in contrast to the normally developed fetal hypophysis. Apparently the hypophyseal fossa plays an important role in determining the form and dimensions of the normal fetal gland. Since this fossa is lacking or at the most only feebly developed in anencephaly, the hypophysis is flattened and spreading. For this reason it is obvious that the flattened surface might permit the gland to keep its earlier fetal shape as it appears to do. The gland of the normal fetus is known to consist of three lobes and, in addition to the main body of the gland, a pars tuberalis. Likewise the. hypophysis of the anencephalic may be comprised of three lobes but not a pars tuberalis. It has been shown that a pars nervosa occurred in only six of the seventeen cases. The anterior lobe may then be said to form the main bulk of the hypophysis. The pars intermedia of this abnormal gland may or may not be present. The residual lumen (hypophyseal cavity) likewise is not always in evidence. The lobes of the hypophysis may appear qualitatively similar to the normal (with the exception of vascularity and fibrous tissue of the pars anterior) but vary considerably in quantity both relative and absolute.
 


The shape of the anencephalic hypophysis is in contrast to the
TABLE 4
normally developed fetal hypophysis. Apparently the hypophyseal
fossa plays an important role in determining the form and dimensions of the normal fetal gland. Since this fossa is lacking or at the
most only feebly developed in anencephaly, the hypophysis is flatHYPOPHY SIS OF THE ANENCEPHALIC FETUS 2 5


tened and spreading. For this reason it is obvious that the flattened
A Comparison of the Observed Average Values for the Weight of the Anencephalio H ypophysis with that of the Normal Fetal H ypophysis According to Age in
surface might permit the gland to keep its earlier fetal shape as it


appears to do.
Fetal Months . Weight of the anen- . Weight of the normal Differences in Age 1“ fetal Num_ cephalic hypophysis . Num_ fetal hypophysis weight between m°nth5 be, of mg. be, of mg. anencephalic cases and normal fetal hypophyses Range Mean mg.
The gland of the normal fetus is known to consist of three lobes


and, in addition to the main body of the gland, a pars tuberalis.
8 16.o— 41.3 30.1 +12.2 16 3o.2— 52.7 42.4 +16.1 12 42.4— 62.3 55.5 — 0.3 13 58.2-121.2 81.2 . . . 12 78.5—13o.1 95.6
Likewise the. hypophysis of the anencephalic may be comprised of
three lobes but not a pars tuberalis. It has been shown that a pars


TABLE 4
1 112.6 112.6 + 0.6


A Comparison of the Observed Average Values for the Weight of the Anencephalio
H ypophysis with that of the Normal Fetal H ypophysis According to Age in


Fetal Months
. Weight of the anen- . Weight of the normal Differences in
Age 1“ fetal Num_ cephalic hypophysis . Num_ fetal hypophysis weight between
m°nth5 be, of mg. be, of mg. anencephalic
cases and normal
fetal hypophyses
Range Mean mg.


8 16.o— 41.3 30.1 +12.2
16 3o.2— 52.7 42.4 +16.1
12 42.4— 62.3 55.5 — 0.3
13 58.2-121.2 81.2 . . .
12 78.5—13o.1 95.6


1 112.6 112.6 + 0.6
Tables 4 and 5 illustrate by a comparison of observed averages the absolute volumes of the normal and abnormal gland. The total weight of the abnormal hypophysis for the fifth to the sixth fetal months exceeds the weight of the normal gland by 12.2 mg. When the average weight is corrected for blood in the pars anterior it checks with the corrected weight value for the normal. The average weight for the sixth to the seventh fetal months is greater than the normal by 16.1 mg. When these averages are corrected for vascularity, the anencephalic exceeds the normal weight by 0.65 mg. The absolute averages for the seventh to the eighth fetal months are about the same. The corrected values show the normal to be more than the anencephalic hypophysis in volume by 13.57 mg. Since there are no specimens between the age limits of the eighth and the tenth fetal months, a comparison is not justified. The weight of the postmature specimen is about the same when compared with a normal of the same age. After correction for vascularity the normal exceeds the total weight of the gland in anencephaly by 26.3 mg.




nervosa occurred in only six of the seventeen cases. The anterior
lobe may then be said to form the main bulk of the hypophysis. The
pars intermedia of this abnormal gland may or may not be present.
The residual lumen (hypophyseal cavity) likewise is not always in
evidence. The lobes of the hypophysis may appear qualitatively
similar to the normal (with the exception of vascularity and fibrous
tissue of the pars anterior) but vary considerably in quantity both
relative and absolute.


Tables 4 and 5 illustrate by a comparison of observed averages the
absolute volumes of the normal and abnormal gland. The total
weight of the abnormal hypophysis for the fifth to the sixth fetal
months exceeds the weight of the normal gland by 12.2 mg. When
the average weight is corrected for blood in the pars anterior it
checks with the corrected weight value for the normal. The average
weight for the sixth to the seventh fetal months is greater than the
normal by 16.1 mg. When these averages are corrected for vascularity, the anencephalic exceeds the normal weight by 0.65 mg. The
absolute averages for the seventh to the eighth fetal months are


TABLE 5
TABLE 5


A Comparison of the Average Total Weight of the Anencephalic H ypophysis with
A Comparison of the Average Total Weight of the Anencephalic H ypophysis with the Normal Fetal Hypophysis after each has been Corrected for Vascularity
the Normal Fetal Hypophysis after each has been Corrected
for Vascularity


Observed average
Observed average




. . Qbserved av e Age in fetal weights of the a_ne1_1- weights of the normal Rggfggzsebigréiig
. . Qbserved av e Age in fetal weights of the a_ne1_1- weights of the normal Rggfggzsebigréiig m°nth5 Num- cephahc hypophysls Num- hypophysis as corrected for vasber of ’'‘3- ber of _r "'15- _ cularity of the anencases I cases cc hahc and normal Range Uncor- Corrected etal hypophyses rected mg. 5 to 6 . . . . . . 6 8 30.10 26.35 =*= 0.00 6 to 7 . . . . . . 6 16 42.4 35.45 + 0.65 7 to 8 . . . . . . 4 12 55.5 47.77 -13.57 8 to 9 . . . . . . 13 81.2 67.89 ... . 9 to 10 12 95.6 79.93 10.16 . . . . . . . 1 1 112.6 98.12 -26.32 TABLE 6
m°nth5 Num- cephahc hypophysls Num- hypophysis as corrected for vasber of ’'‘3- ber of _r "'15- _ cularity of the anencases I cases cc hahc and normal
Range Uncor- Corrected etal hypophyses
rected mg.
5 to 6 . . . . . . 6 8 30.10 26.35 =*= 0.00
6 to 7 . . . . . . 6 16 42.4 35.45 + 0.65
7 to 8 . . . . . . 4 12 55.5 47.77 -13.57
8 to 9 . . . . . . 13 81.2 67.89 ... .
9 to 10 12 95.6 79.93  
10.16 . . . . . . . 1 1 112.6 98.12 -26.32
TABLE 6


Relative Volume of the Blood in the Pars anterior of the Normal Fetal H ypophysis
Relative Volume of the Blood in the Pars anterior of the Normal Fetal H ypophysis


L: 1—
L: 1— 4- 1
4- 1


Relative volume
Relative volume


Necropsy number Total bcoiy length Rela.(§vtelc:r.0:(Eume o tgr?°:f
Necropsy number Total bcoiy length Rela.(§vtelc:r.0:(Eume o tgr?°:f . ,, W mu 24-165 . . . . . . . . . . . . . . . . . . . . . . . . . . 28.0 17.97 82.03
. ,, W mu
24-165 . . . . . . . . . . . . . . . . . . . . . . . . . . 28.0 17.97 82.03


24-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.0 12.15 87.85
24-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.0 12.15 87.85
Line 484: Line 262:




about the same. The corrected values show the normal to be more
than the anencephalic hypophysis in volume by 13.57 mg. Since
there are no specimens between the age limits of the eighth and the
HYPOPHYSTS OF THE ANENCEPHALIC FETUS 27


tenth fetal months, a comparison is not justified. The weight of the
It is obvious that if the amount of blood in the pars anterior be considered, the gland of the abnormal fetus usually is less in weight than the normal from a fetus of corresponding age. The same conclusion holds for the weights of the anterior lobes of normal and abnormal fetuses. The average relative amount of blood present in the normal fetal hypophysis is 16.4 per cent for eleven determinations. This figure is nearly two and one-half times less than the average for the pars anterior of the anencephalic gland.
postmature specimen is about the same when compared with a normal of the same age. After correction for vascularity the normal
exceeds the total weight of the gland in anencephaly by 26.3 mg.


It is obvious that if the amount of blood in the pars anterior be
==Summary==
considered, the gland of the abnormal fetus usually is less in weight
than the normal from a fetus of corresponding age. The same conclusion holds for the weights of the anterior lobes of normal and
abnormal fetuses. The average relative amount of blood present in
the normal fetal hypophysis is 16.4 per cent for eleven determinations. This figure is nearly two and one-half times less than the
average for the pars anterior of the anencephalic gland.
 
SUMMARY


The results obtained by this study may be summarized as follows:
The results obtained by this study may be summarized as follows:
Line 506: Line 271:
1 . An hypophysis is present in anencephalic fetuses.
1 . An hypophysis is present in anencephalic fetuses.


2. It is extremely variable in weight. If the weight is corrected
2. It is extremely variable in weight. If the weight is corrected for vascularity it is usually less than the weight of the normal fetal hypophysis which has also been corrected.
for vascularity it is usually less than the weight of the normal fetal
hypophysis which has also been corrected.


3. The pars nervosa is lacking in the majority of cases. When
3. The pars nervosa is lacking in the majority of cases. When present its relative and absolute volumes are considerably less than those of the normal.
present its relative and absolute volumes are considerably less than
those of the normal.


4. The pars intermedia is variable in both occurrence and volume.
4. The pars intermedia is variable in both occurrence and volume. It may be present in a gland in which there is no pars nervosa in ‘evidence.
It may be present in a gland in which there is no pars nervosa in
‘evidence.


5. The pars anterior comprises most of the gland volume and
5. The pars anterior comprises most of the gland volume and apparently the total gland volume in some instances.
apparently the total gland volume in some instances.


6. The average relative volume of blood present in the anterior
6. The average relative volume of blood present in the anterior lobe is about 39 per cent of the volume of that lobe.
lobe is about 39 per cent of the volume of that lobe.


The writer wishes to acknowledge his indebtedness to Professors R. E. Scammon
The writer wishes to acknowledge his indebtedness to Professors R. E. Scammon and A. T. Rasmussen for their many valuable suggestions during the course of this study.
and A. T. Rasmussen for their many valuable suggestions during the course of this
study.


REFERENCES
==References==


1. Ballantyne, A. Manual of ante-natal pathology. Edinburgh, 1902-04.
1. Ballantyne, A. Manual of ante-natal pathology. Edinburgh, 1902-04.


2. Schwalbe, E. Die Morphologie der Missbildungen des Menschen und der
2. Schwalbe, E. Die Morphologie der Missbildungen des Menschen und der Tiere. Jena, 1909, iii, 108.
Tiere. Jena, 1909, iii, 108.


3. Haberfeld, W. Zur Pathologie des Canalis craniopharyngeus. Frankfurt.
3. Haberfeld, W. Zur Pathologie des Canalis craniopharyngeus. Frankfurt. Ztschr. f. Path., 1910, iv, 96. 28
Ztschr. f. Path., 1910, iv, 96.
28


IO.
IO.
Line 544: Line 296:




Brown, F. J. The anencephalic syndrome in its relation to apituitarism.
Brown, F. J. The anencephalic syndrome in its relation to apituitarism. Edinburgh Med. J., 1920, N. S. xxv, 296.
Edinburgh Med. J., 1920, N. S. xxv, 296.


Mauksch, H. Das Verhalten der Hypophyse und des Canalis craniopharyngeus in neun F iillen von Kranioschisis untersucht. Anat. Anz., 1921, liv,
Mauksch, H. Das Verhalten der Hypophyse und des Canalis craniopharyngeus in neun F iillen von Kranioschisis untersucht. Anat. Anz., 1921, liv, 248.
248.


Kohn, A. Anencephalie und Nebenniere. Arch. f. milero. Anat. u. Entwcklngsmechm, I924, cii, 113.
Kohn, A. Anencephalie und Nebenniere. Arch. f. milero. Anat. u. Entwcklngsmechm, I924, cii, 113.


Wrete, M. Ein Fall von Encephalo-Myeloschisis totalis bei einem menschlichem Embryo in der 7. Woche der Schwangerschaft. Ztschr. f. mikro.
Wrete, M. Ein Fall von Encephalo-Myeloschisis totalis bei einem menschlichem Embryo in der 7. Woche der Schwangerschaft. Ztschr. f. mikro. Anat. Forsch., I924, i, 563.
Anat. Forsch., I924, i, 563.
 
N afiagas, J: C. A comparison of the growth of the body dimensions of anencephalic human fetuses with normal fetal growth as determined by graphic analysis and empirical formulae. Am. J. Anat., I92 5-26, xxxv, 45 5. Scammon, R. E., and Calkins, L. A. Simple empirical formulae for expressing the lineal growth of the human fetus. Proc. Soc. Exper. Biol. and Med., 1922-23, xx, 353.


N afiagas, J: C. A comparison of the growth of the body dimensions of
Rasmussen, A. T., and Herrick, R. A method for the volumetric study of the human hypophysis cerebri with illustrative results. Proc. Soc. Exper. Biol. and M ed., I921-22, xix, 416.
anencephalic human fetuses with normal fetal growth as determined by
graphic analysis and empirical formulae. Am. J. Anat., I92 5-26, xxxv, 45 5.
Scammon, R. E., and Calkins, L. A. Simple empirical formulae for expressing the lineal growth of the human fetus. Proc. Soc. Exper. Biol. and
Med., 1922-23, xx, 353.


Rasmussen, A. T., and Herrick, R. A method for the volumetric study of
Covell, W. P. Quantitative studies on the human prenatalhypophysis and hypophyseal fossa. (Abstract.) Anat. Rec., 1926, xxxii, 23o.
the human hypophysis cerebri with illustrative results. Proc. Soc. Exper.
Biol. and M ed., I921-22, xix, 416.


Covell, W. P. Quantitative studies on the human prenatalhypophysis and
hypophyseal fossa. (Abstract.) Anat. Rec., 1926, xxxii, 23o.




Revision as of 16:27, 22 June 2018

Embryology - 16 Apr 2024    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

Covell WP. A quantitative study of the hypophysis of the human anencephalic fetus. (1927) Am J Pathol. 3(1) :17-28. PMID 19969726

Online Editor 
Mark Hill.jpg
This historic 1927 paper by Covell describes the hypophysis of the human anencephalic fetus.




Modern Notes: pituitary | neural abnormalities

Endocrine Links: Introduction | BGD Lecture | Science Lecture | Lecture Movie | pineal | hypothalamus‎ | pituitary | thyroid | parathyroid | thymus | pancreas | adrenal | endocrine gonad‎ | endocrine placenta | other tissues | Stage 22 | endocrine abnormalities | Hormones | Category:Endocrine
Historic Embryology - Endocrine  
1903 Islets of Langerhans | 1903 Pig Adrenal | 1904 interstitial Cells | 1908 Pancreas Different Species | 1908 Pituitary | 1908 Pituitary histology | 1911 Rathke's pouch | 1912 Suprarenal Bodies | 1914 Suprarenal Organs | 1915 Pharynx | 1916 Thyroid | 1918 Rabbit Hypophysis | 1920 Adrenal | 1935 Mammalian Hypophysis | 1926 Human Hypophysis | 1927 Adrenal | 1927 Hypophyseal fossa | 1930 Adrenal | 1932 Pineal Gland and Cysts | 1935 Hypophysis | 1935 Pineal | 1937 Pineal | 1935 Parathyroid | 1940 Adrenal | 1941 Thyroid | 1950 Thyroid Parathyroid Thymus | 1957 Adrenal


Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

A Quantitative Study of the Hypophysis of the Human Anencephalic Fetus

W. P. Covell.

From the Department of Anatomy, University of M innesota, M innoapolis, Minn.

Introduction

The question of the presence or the absence of the hypophysis in the anencephalic fetus has been of special significance in connection with the subject of the function and interrelationship of the ductless glands. Some have even attributed this abnormality to a disturbance of the endocrine system. Previous to 1921 the general belief was that an hypophysis was frequently absent in anencephalics and when present was usually described as being diflerent from the normal gland. No quantitative methods have been applied, consequently the literature is based on qualitative observations only.

It is the purpose of this investigation to apply quantitative methods to these abnormal specimens and when the organ is present to compare it with that of the normal. In order to bring the subject to its present status the principal contributions are summarized below.

Review of the Literature

Ballantyne 1 has described forty-five anencephalic fetuses and states that “ the hypophysis rarely occurs.” Schwalbe 2 says the hypophysis is sometimes present and in a large number of cases there is accessory hypophyseal tissue. Haberfeld 3 examined three cases of anencephaly and reported an hypophysis as present in each. In one instance a pars nervosa was found in the upper part of the cralnio-.

pharyngeal canal. The glandular portions, in this instance,‘ extended through the canal and only a small polyp was present at either end. Brown 4 examined five specimens of anencephalic fetuses and failed to find the hypophysis. He concluded, therefore, that the condition

of apituitarism was normal for anencephaly. Mauksch 5 found an hypophysis in nine cases of this monstrosity. In five of these, he described a pharyngeal hypophysis with a par ‘ Received for publication September 28, 1926.

tially or totally patent craniopharyngeal canal which contained blood vessels and hypophyseal tissue. All three lobes were present in only two of the nine glands. When there was no posterior lobe (pars nervosa), he did not observe a pars intermedia and thus considered the hypophysis in such cases to consist of pars anterior only. In one instance he found the upper surface of the connective tissue capsule to contain a small neuroglial structure which was in contact neither with the brain tissue nor with the hypophysis. There was no intermediate glandular portion discernible. In two of the specimens the pars nervosa was found to be a small basophilic structure of neuroglial elements located on a concavity of the glandular part. He noticed a pars intermedia in contact with the latter but thought it appeared abnormal and incomplete. He found the pars anterior to be very vascular and the parenchyma in the form of cords surrounded by sinuses filled with blood.

Kohn 5 verified the report of Mauksch 5 as to the occurrence of the hypophysis. He investigated eleven cases of anencephaly and found an hypophysis in each. He likewise found the gland to be abnormal in structure. In only three of the specimens did he find a pars nervosa. He concluded that the pars intermedia and pars nervosa as well as the pars tuberalis are usually lacking. If the pars nervosa was not present, he thought the intermediate lobe was also absent. He reported that the cells of the pars anterior were normally differentiated. In addition he described a cell which he thought occurred but seldom in the normal fetal hypophysis. According to him, this latter mentioned type was present in large numbers in the anencephalic hypophysis. Such a cell type appeared to be larger than the chromophile cells and stained slightly basophilic or neutrophilic with Mallory’s triple connective tissue stain.

Wrete 7 found a hypophysis to be present in a case of encephalomyeloschisis totalis of an embryo of the seventh week. ‘

Material and Methods

The material used in this study consisted of thirty-two anencephalic fetuses which were obtained from the Department of Pathology, University of Minnesota. Most of the material had been previously preserved in IO per cent formalin in which it had remained for a year or more in some instances.

Twenty-seven of the thirty-two fetuses were females, the remaining five being males. They ranged in age from about the fifth fetal month to full term. The ages of the fetuses were determined by means of a formula used by Nafiagas 3 for conversion of the leg length (distance from the greater trochanter to the base of the heel) of the anencephalic fetus into total body length of a normal fetus. Then by applying to the result the formula of Scammon and Calkins 9 for converting the crown-heel measurement into terms of age in fetal months, the latter was determined. The formula given

by Nafiagas is as follows:

Crown-heel (cm.) = 3%: leg length (cm.) + 0.7

The formula developed by Scammon and Calkins gives the age in fetal months or “T” when “L” is the crown-heel measurement in centimeters.


The relative and absolute volumes of the parts of the gland were determined by the paper-weight method as described by Rasmussen and Herrick.” For a comparison of the abnormal with the normal gland, data available (Covell 11) on the hypophyses of sixty-two normal fetuses were used.

The relative amount of blood in the pars anterior of the hypophysis was approximated by projecting areas of sections 10 microns thick of this portion of the gland at a magnification of about 7 50 times. five fields were chosen on each of three different levels, two of the fields being near the periphery of the gland, one centrally located and the remaining two intermediate between the periphery and central parts. The vascular areas in each of the fields were outlined with a hard lead pencil. The relative amount of blood in the pars anterior was then ascertained by weighing the paper areas representing the blood and those representing the fibrous and glandular tissue, and dividing the weight of the vascular areas in paper by the total paper—weight.

For the normal gland, a section approximately one-half of the way through the gland was used and five fields were outlined on it. The relative volume of the blood was found to be very nearly identical withfthat determined by the use of the three levels and the fifteen fields.

General Description of the Hypophysis

Of the thirty-two specimens of the anencephalic fetus examined, an hypophysis was present in each instance. Such findings are in accordance with the more recent investigations on this monstrosity but in contradiction to the earlier work. It would appear that the earlier work was of a gross nature so that the small amount of hypophyseal tissue which lies on the malformed basis cranii may have been overlooked.

The hypophyseal fossa is usually lacking or at the most only feebly developed. No trace of the clinoid processes or dorsum sella is evident. Occasionally the anterior clinoid processes are slightly developed and so form a narrow fossa for the most anterior portion of the gland. A diaphragma sella is lacking, probably because of the absence of the clinoid processes.

The hypophysis may then be said, to lie on a flattened sella turcica covered over by membranes, vascular tissue and in some instances a small amount of brain tissue. Macroscopically it presents a flat triangular shape with the apex directed dorsally. The base of this mass is formed by two lateral spreading portions and the apex of one central mass. Such a shape no doubt is of embryologic significance because it is known that the glandular portion (pars anterior) grows in early fetal life by means of two lateral and one central buds from the ventral side of Rathke’s pouch. This form subsequently changes in the course of normal development because the gland soon approximates the shape of the fossa in which it is situated. Macroscopically, the neural elements (pars nervosa) of the gland, when present, appear as an irregularly shaped opaque mass on the dorso— posterior surface of the larger glandular portion. An infundibular stalk is lacking and only a thin cord of membrane remains to attach the gland to the overlying tissues. Microscopically, the hypophysis of the anencephalic fetus presents several striking differences when compared with the gland from the normal fetus. In the first place, the three lobes may not all be present. In only six of the seventeen specimens studied did the hypophysis consist of three lobes. In eleven instances there was no pars nervosa evident. In four of the latter a pars intermedia could be distinguished, whfle in the remaining seven the pars anterior appeared to comprise the total gland volume.

The extreme vascularity of the gland, particularly of the pars anterior, presents a marked difierence from that of the normal. Especially about the periphery of the anterior lobe the sinuses are dilated to such an extent that the parenchyma is reduced to narrow epithelial cords which appear to be surrounded by blood spaces. Toward the center of the pars anterior, the sinuses are usually less dilated with blood.

Trabeculae radiate through the pars anterior and contain numerous blood vessels. Occasionally there is a band of fibrous tissue separating the main bulk of the anterior lobe from the thin epithelial strip which borders the hypophyseal cavity. Likewise the pars intermedia may be separated from the pars nervosa by a thin band of fibrous tissue. The capsule of connective tissue about the gland is well developed and appears to be more extensive than in the normal hypophysis.

Relative and Absolute Volumes of the Gland and its Parts

A. Weight of the total gland. In Table I are given the absolute volumes of seventeen hypophyses and their lobes. It is evident that there is considerable individual variation in the total weight of the gland for fetuses of about the same age. The six observations for fetuses of the fifth to the sixth fetal months have a range of 29. 3 to 69.6 mg. and an average of 42. 3 mg. The range as observed from six specimens of the sixth to the seventh fetal months is 29.2 to 85.6 mg. with an average of 58.5 mg. Four hypophyses from fetuses of the seventh to the eighth fetal months show a range of 3 5.0 to 7 3.8 mg. and an average of 5 5.1 mg. The intervals from the eighth fetal month to birth are represented by only one observation. The age of the latter was calculated as 10.16 fetal months and the hypophysis weight was found to be 113.2 mg.

B. Weight of the pars anterior. Considerable variation is likewise evident in the weights of the pars anterior. For the fifth to the sixth months, the range is 29.3 to 65.4 mg. and the average is 40.9 mg. The weights of this lobe in specimens of the sixth to the seventh fetal months show a range of 28.9 to 85.6 mg. with an average of 57.8 mg. From the seventh to the eighth fetal months, the range is 34.6 to

TABLE 1

Absolute Volume of the Gland and its Parts in Seventeen Specimens of Anencephaly

Leg r£‘(’)‘tl:’l Age in Hygggh- a.I:1l:::l§0l' ncfrgssa Case number Sex length length fetal weight weight weight weight on computed months mg. mg. mg. mg. cm. c9 . . . . . . . . . . . . . . F 10.2 | 25.34 5.38 38.0 36.6 0.9 0.5

c2 . . . . . . . . . . . . . . M 10.7 26.51 5.56 41.6 40.8 0.8

CIO . . . . . . . . . . . . . F 11.0 27.20 5.66 37.3 37.3 . . . . . .

c4—17 . . . . . . . . . . . F 11.4 I 28.14 5.81 69.6 65.4 2.5 1.7

c23—184 . . . . . . . . . F 11.7 28.83 5.93 29.3 29.3 . . . . . .

c4 . . . . . . . . . . . . . . F 11.7 I 28.83 5.93 38.4 36.1 1.3 1.0

c23—183 . . . . . . . . . F 12.0 29.53 6.05 72.7 69.5 2.3 0.9

c7 . . . . . . . . . . . . . . F 12.7 | 31.16 6.32 50.4 50.4 . . .

c1 . . . . . . . . . . . . . . F 12.9 31.63 6.39 29.2 28.9 0.3

c6 . . . . . . . . . . . . . . M 13.1 32.09 6.47 41.2 40.3 0.9

c8 . . . . . . . . . . . . . F 13.2 32.33 6.51 85.6 85.6

cm . . . . . . . . . . . . . F 13.7 33.49 6.72 72.2 72.2

c15 . . . . . . . . . . . . . M 14.5 35.35 7.05 68.9 68.9 . . .

c3 . . . . . . . . . . . . . . F 14.6 35.58 7.08 35.0 34.6 0.4

c5 . . . . . . . . . . . . . . F 15.5 37.67 7.47 42.9 41.4 1.5 . . .

CI4 . . . . . . . . . . . . . F 16.6 40.23 7.95 73.8 71.4 2.0 0.4

c4—18 . . . . . . . . . . . F 21.2 50.93 10.16 113.2 106. 1.6 5.3 TABLE 2

Relative Volumes of the Lobes of the Anencephalic Hypophysis


Case number I 3 in Pars anterior Pars inter-media Pars nervosa etal months per cent per cent per cent c9 . . . . . . . . . . . . . . . . . . . . . . . 5 38 96.33 2 36 1 31

c2 . . . . . . . . . . . . . . . . . . . . . . . 5 56 98.08 1 92

c4—17 . . . . . . . . . . . . . . . . . . . . 5.81 93.97 3.59 2.44

c4 . . . . . . . . . . . . . . . . . . . . . . . 5.93 94.01 3.39 2.60

c23—183 . . . . . . . . . . . . . . . . . . 6 05 95.58 3 14 1.28

c1 . . . . . . . . . . . . . . . . . . . . . . . 6 39 98.97 1 03

c6 . . . . . . . . . . . . . . . . . . . . . . . 6 47 97.82 2 18

c3 . . . . . . . . . . . . . . . . . . . . . . . 7 08 98.86 1 14

c5 . . . . . . . . . . . . . . . . . . . . . . . 7.47 96.50 3 50 . .

c14 . . . . . . . . . . . . . . . . . . . . . . 7.95 96.75 2 71 0.54


71.4 mg. and the average is 54.1 mg. In the one gland of a fetus of 10.16 fetal months the weight of the pars anterior is 106.3 mg.

C. Weights of the partes intermedia and nervosa. The absolute volumes of the partes intermedia and nervosa are of very little significance because of the extreme variations. They are, however, of importance for a comparison with the normal Weights.

D. Relative volumes of the parts (lobes). The relative volumes of the various lobes of the hypophysis are given in Table 2. Because of the limited number of cases and the apparent irregularities in the partes intermedia and nervosa, the relative volumes will be con 3 sidered without respect to fetal age. The anterior lobe comprises about 93.9 to 1oo per cent of the total gland volume. In the eleven instances in which a pars intermedia was present, it is seen to comprise 1.14 to 3.59 per cent of the total gland Weight. The pars nervosa which occurs in only six of the seventeen cases varies in relative volume from 0.54 to 4.69 per cent. From the above percentage values it is evident that most of the hypophysis is pars anterior and only a small part is intermediate and posterior lobes. In only one instance does the pars nervosa exceed the pars intermedia in relative as well as absolute volume.

Volumetric Analysis of the Pars Anterior

A. Relative volume of the blood. Because of the engorged sinuses of the pars anterior and the prominent trabeculae, it was found necessary to determine the relative amounts of each. This was accomplished by means of the paper-weight method as already described. The results are tabulated in Table 3. The figures for the relative vascularity appear to vary from about 2 5 to 50 per cent for individual estimations. The average for the fifteen determinations is 38.98 per cent.


B. Relative volume of the trabeculae. The relative amounts of trabeculae present in the gland range from about o. 5 per cent to nearly 4 per cent. The average for the series is 1. 58 per cent. This figure represents only the larger masses of fibrous tissue in the pars anterior. The finer connective tissue framework is included with the percentage figure for the parenchyma, the average for which is 59.44 per cent of the volume of the pars anterior. The range is approximately 45 to 77 per cent.


It is thus obvious that considerable of the absolute volume of the anterior lobe is due to the presence of blood in the sinuses. From the relative averages cited above, it may be said that approximately two-fifths of this part of the gland is composed of vascular and fibrous stroma. The remaining three-fifths is comprised of parenchyma and finer fibrous stroma. Such an analysis is of value in determining the actual amount of glandular tissue which is present. The large amounts of blood apparently influence the volume of the anencephalic hypophysis to a marked degree.


TABLE 3

Volumetric Analysis of the Components of the Pars Anterior


Case number U Blood Trabeculae filll) (1_"g1b°:)Yu:“;;'§ga I fier cent per cent per cent c9 . . . . . . . . . . . . . . . . . .8 . . . . . . . . . . . . 38.18 3.98 57.84

c2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' 40.37 V 0.49 59.14

c4—17 . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.81 2.02 54.17

c4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 37.83 1.12 61.05

c23—183 . . . . . . . . . . . . . . . . . . . . . . . . . 36.71 2.34 60.95

c7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.48 1.03 64.49

c1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.56 1.40 77.04

c6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.67 0.75 52.58

c8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53.00 2.16 44.84

cm . . . . , . . . . . . . . . . . . . . . . . . . . . . . . 40.05 0.97 58.98

c15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37.81 1.59 60.60

c3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.22 1.46 71.32

c5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.93 1.47 59.60

cm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.63 2.00 61.37

c4-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.46 0.97 47.57

Mean . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.98 1.58 59.44


Discussion

The shape of the anencephalic hypophysis is in contrast to the normally developed fetal hypophysis. Apparently the hypophyseal fossa plays an important role in determining the form and dimensions of the normal fetal gland. Since this fossa is lacking or at the most only feebly developed in anencephaly, the hypophysis is flattened and spreading. For this reason it is obvious that the flattened surface might permit the gland to keep its earlier fetal shape as it appears to do. The gland of the normal fetus is known to consist of three lobes and, in addition to the main body of the gland, a pars tuberalis. Likewise the. hypophysis of the anencephalic may be comprised of three lobes but not a pars tuberalis. It has been shown that a pars nervosa occurred in only six of the seventeen cases. The anterior lobe may then be said to form the main bulk of the hypophysis. The pars intermedia of this abnormal gland may or may not be present. The residual lumen (hypophyseal cavity) likewise is not always in evidence. The lobes of the hypophysis may appear qualitatively similar to the normal (with the exception of vascularity and fibrous tissue of the pars anterior) but vary considerably in quantity both relative and absolute.


TABLE 4

A Comparison of the Observed Average Values for the Weight of the Anencephalio H ypophysis with that of the Normal Fetal H ypophysis According to Age in

Fetal Months . Weight of the anen- . Weight of the normal Differences in Age 1“ fetal Num_ cephalic hypophysis . Num_ fetal hypophysis weight between m°nth5 be, of mg. be, of mg. anencephalic cases and normal fetal hypophyses Range Mean mg.

8 16.o— 41.3 30.1 +12.2 16 3o.2— 52.7 42.4 +16.1 12 42.4— 62.3 55.5 — 0.3 13 58.2-121.2 81.2 . . . 12 78.5—13o.1 95.6

1 112.6 112.6 + 0.6



Tables 4 and 5 illustrate by a comparison of observed averages the absolute volumes of the normal and abnormal gland. The total weight of the abnormal hypophysis for the fifth to the sixth fetal months exceeds the weight of the normal gland by 12.2 mg. When the average weight is corrected for blood in the pars anterior it checks with the corrected weight value for the normal. The average weight for the sixth to the seventh fetal months is greater than the normal by 16.1 mg. When these averages are corrected for vascularity, the anencephalic exceeds the normal weight by 0.65 mg. The absolute averages for the seventh to the eighth fetal months are about the same. The corrected values show the normal to be more than the anencephalic hypophysis in volume by 13.57 mg. Since there are no specimens between the age limits of the eighth and the tenth fetal months, a comparison is not justified. The weight of the postmature specimen is about the same when compared with a normal of the same age. After correction for vascularity the normal exceeds the total weight of the gland in anencephaly by 26.3 mg.



TABLE 5

A Comparison of the Average Total Weight of the Anencephalic H ypophysis with the Normal Fetal Hypophysis after each has been Corrected for Vascularity

Observed average


. . Qbserved av e Age in fetal weights of the a_ne1_1- weights of the normal Rggfggzsebigréiig m°nth5 Num- cephahc hypophysls Num- hypophysis as corrected for vasber of ’'‘3- ber of _r "'15- _ cularity of the anencases I cases cc hahc and normal Range Uncor- Corrected etal hypophyses rected mg. 5 to 6 . . . . . . 6 8 30.10 26.35 =*= 0.00 6 to 7 . . . . . . 6 16 42.4 35.45 + 0.65 7 to 8 . . . . . . 4 12 55.5 47.77 -13.57 8 to 9 . . . . . . 13 81.2 67.89 ... . 9 to 10 12 95.6 79.93 10.16 . . . . . . . 1 1 112.6 98.12 -26.32 TABLE 6

Relative Volume of the Blood in the Pars anterior of the Normal Fetal H ypophysis

L: 1— 4- 1

Relative volume

Necropsy number Total bcoiy length Rela.(§vtelc:r.0:(Eume o tgr?°:f . ,, W mu 24-165 . . . . . . . . . . . . . . . . . . . . . . . . . . 28.0 17.97 82.03

24-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.0 12.15 87.85

24-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.0 9.86 90.14

23-849 . . . . . . . . . . . . . . . . . . . . . . . . . . 39.0 26.87 73.12

22-323 . . . . . . . . . . . . . . . . . . . . . . . . . . 45.0 10.74 89.26

24-795 . . . . . . . . . . . . . . . . . . . . . . . . . . 45.5 18.82 81.18

24-72 . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.0 16.71 83.29

23-224 . . . . . . . . . . . . . . . . . . . . . . . . . . ‘ 49.0 12.12 87.88

1746 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51.5 21.36 78.64

23-408 . . . . . . . . . . . . . . . . . . . . . . . . . . 55.0 16.41 83.59

23-535 . . . . . . . . . . . . . . . . . . . . . . . . . . 60.0 17.13 82.87

Mean . . . . . . . . . . . . . . . . . . . . . . . . . 16.40 83.60


It is obvious that if the amount of blood in the pars anterior be considered, the gland of the abnormal fetus usually is less in weight than the normal from a fetus of corresponding age. The same conclusion holds for the weights of the anterior lobes of normal and abnormal fetuses. The average relative amount of blood present in the normal fetal hypophysis is 16.4 per cent for eleven determinations. This figure is nearly two and one-half times less than the average for the pars anterior of the anencephalic gland.

Summary

The results obtained by this study may be summarized as follows:

1 . An hypophysis is present in anencephalic fetuses.

2. It is extremely variable in weight. If the weight is corrected for vascularity it is usually less than the weight of the normal fetal hypophysis which has also been corrected.

3. The pars nervosa is lacking in the majority of cases. When present its relative and absolute volumes are considerably less than those of the normal.

4. The pars intermedia is variable in both occurrence and volume. It may be present in a gland in which there is no pars nervosa in ‘evidence.

5. The pars anterior comprises most of the gland volume and apparently the total gland volume in some instances.

6. The average relative volume of blood present in the anterior lobe is about 39 per cent of the volume of that lobe.

The writer wishes to acknowledge his indebtedness to Professors R. E. Scammon and A. T. Rasmussen for their many valuable suggestions during the course of this study.

References

1. Ballantyne, A. Manual of ante-natal pathology. Edinburgh, 1902-04.

2. Schwalbe, E. Die Morphologie der Missbildungen des Menschen und der Tiere. Jena, 1909, iii, 108.

3. Haberfeld, W. Zur Pathologie des Canalis craniopharyngeus. Frankfurt. Ztschr. f. Path., 1910, iv, 96. 28

IO.

II.


Brown, F. J. The anencephalic syndrome in its relation to apituitarism. Edinburgh Med. J., 1920, N. S. xxv, 296.

Mauksch, H. Das Verhalten der Hypophyse und des Canalis craniopharyngeus in neun F iillen von Kranioschisis untersucht. Anat. Anz., 1921, liv, 248.

Kohn, A. Anencephalie und Nebenniere. Arch. f. milero. Anat. u. Entwcklngsmechm, I924, cii, 113.

Wrete, M. Ein Fall von Encephalo-Myeloschisis totalis bei einem menschlichem Embryo in der 7. Woche der Schwangerschaft. Ztschr. f. mikro. Anat. Forsch., I924, i, 563.

N afiagas, J: C. A comparison of the growth of the body dimensions of anencephalic human fetuses with normal fetal growth as determined by graphic analysis and empirical formulae. Am. J. Anat., I92 5-26, xxxv, 45 5. Scammon, R. E., and Calkins, L. A. Simple empirical formulae for expressing the lineal growth of the human fetus. Proc. Soc. Exper. Biol. and Med., 1922-23, xx, 353.

Rasmussen, A. T., and Herrick, R. A method for the volumetric study of the human hypophysis cerebri with illustrative results. Proc. Soc. Exper. Biol. and M ed., I921-22, xix, 416.

Covell, W. P. Quantitative studies on the human prenatalhypophysis and hypophyseal fossa. (Abstract.) Anat. Rec., 1926, xxxii, 23o.


Cite this page: Hill, M.A. (2024, April 16) Embryology Paper - A quantitative study of the hypophysis of the human anencephalic fetus. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Paper_-_A_quantitative_study_of_the_hypophysis_of_the_human_anencephalic_fetus

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
Retrieved from ‘https://embryology.med.unsw.edu.au/embryology/index.php?title=Paper_-_A_quantitative_study_of_the_hypophysis_of_the_human_anencephalic_fetus&oldid=344684’
Powered by MediaWiki